The present invention relates generally to solid-state devices for converting or extracting energy from hydrocarbon-oxidizer reactions. More specifically, this invention relates to a significant improvement of the process for the efficient conversion and extraction of energy in the form of optical emissions and of coherent radiation and from reactants such as hydrocarbons, hydrogen or other combustible materials reacting on a catalyst surface with air or other oxidizers.
One method to convert chemical reactant energy directly into useful work such as electricity uses electrochemical couples such as batteries and fuel cells. In this method, a substantial fraction of the reactant bond energies may be converted directly into electrical potential. However, the physical chemistry underlying these processes limits the rate of such conversion substantially. The result is a power per mass and power per volume that is orders of magnitude smaller than that of a mechanical engine.
Another method uses gas dynamic processes to convert chemical energy directly into a dynamic state exhibiting a population inversion. The energy is extracted from this system as coherent radiation. However, the reactants and exhausts of this method are usually dangerous and incompatible with human safety considerations. Moreover, these devices cannot be efficiently miniaturized.
Therefore, it is highly desirable to have a simpler method and system for extracting efficiently without having to use harmful products and without producing hazardous byproducts in the process.
A recent research suggests that certain simple, energetic atoms reacting on a catalytic surface produce products exhibiting a population inversion. An inverted population is the prerequisite for stimulated emission of radiation, which is one method to remove the energy from the reaction and to retain its high degree of usefulness.
One problem in the prior state of technology is the process of creating highly energetic species on the catalyst surface, such as hot atoms and mono-atomic oxygen, that 1) retain a significant amount of the chemical energy for reactions, instead of dissipating it as a heat of adsorption, and 2) that will produce an inverted population as a product of the reaction. The issue in the creation of hot atoms, such as mono-atomic oxygen, is that it usually takes more electrical energy to produce the hot atoms than can be extracted from the resulting chemical reactions.
Research has suggested that mono-atomic, energetic specie reacting with simple adsorbed specie may form vibrationally inverted products, and that this inversion may occur in many systems. For example, research has shown that when gas phase oxygen atoms react with deuterium adsorbed on a tungsten surface, OD radicals are formed in the inverted state, with the highest population appearing at vibrational level 6. This represents a substantial fraction of the available reaction energy being concentrated in the inverted state. Shin, HK, xe2x80x9cVibrationally Excited OD Radicals From The Reaction Of Oxygen-Atoms With Chemisorbed Deuterium On Tungsten,xe2x80x9d Journal Of Physical Chemistry A, v. 102(#13), pp. 2372-2380, Mar. 26, 1998.
Similar research showed that gas phase atomic oxygen reacting with adsorbed hydrogen on the surface produces population inverted, OH radicals within 100 femtoseconds. Ree J, Kim YH, Shin HK, xe2x80x9cDynamics Of Gas-Surface Interactions: Reaction Of Atomic Oxygen With Chemisorbed Hydrogen On Tungsten,xe2x80x9d Journal Of Physical Chemistry A, V. 101(#25), pp. 4523-4534, Jun. 19, 1997.
It was shown in Kim, M. S. and J. Ree, xe2x80x9cReaction of Gas-Phase Atomic Hydrogen with Chemisorbed Hydrogen Atoms on an Iron Surface,xe2x80x9d Bulletin of the Korean Chemical Society, Volume 18, Number 9 (1997), COMMUNICATIONS, pp 985-994, that gas phase atomic hydrogen reacts with chemisorbed hydrogen on an iron surface to form population inverted, desorbed diatomic hydrogen molecules.
It is known that when atomic oxygen in the gas phase reacts with carbon monoxide adsorbed on a platinum catalyst surface, the fraction of reactive collisions producing molecules having vibrational energies corresponding to levels v3=9 to 13 is found to be very high and exhibits a vibrational population inversion. Ree, J.; Y. H. Kim, and H. K. Shin, xe2x80x9cReaction of atomic oxygen with adsorbed carbon monoxide on a platinum surface,xe2x80x9d Journal of Chemical Physics, Jan. 8, 1996, Volume 104, Issue 2, pp. 742-757. This would be useful except for the fact that the mono-atomic oxygen atoms for this reaction must be created using inefficient means, namely electric arcs.
Yet another research has shown that mono-atomic oxygen atoms can be created directly on a catalytic surface by irradiation with UV light. The most probable result of such irradiation is the production of mono-atomic oxygen atoms. The next most probable result is desorption. The issue with this approach is the low efficiency of the generation and conversion of UV light into dissociated oxygen atoms. Tripa, C. Emil, Christopher R. Arumaninayagam, John T. Yates, Jr., xe2x80x9cKinetics measurements of CO photo-oxidation on Pt(111),xe2x80x9d Journal of Chemical Physics, Jul. 22, 1996, Volume 105, Issue 4, pp. 1691-1696.
A related research has also shown that oxygen molecules preferentially adsorb on the step sites of a catalyst such as platinum, and that photo generated mono-atomic oxygen atoms preferentially react with other radicals or molecules also adsorbed on the step sites. Atomic and molecular species generated by the photolysis of aligned molecules adsorbed on crystalline solids tend to move preferentially in particular directions relative to the crystal surface. For example, photo-generated mono-atomic oxygen reacts preferentially with adsorbed CO to make excited state CO2. The feature here is the efficiency of reaction of the hot atoms with other surface reactants. An issue here is the preferential production of hot atoms. Tripa, C. Emil; John T. Yates Jr, xe2x80x9cSurface-aligned reaction of photo generated oxygen atoms with carbon monoxide targets,xe2x80x9d Nature, Vol 398, pages 591-593 (1999) Apr. 15, 1999.
Another research showed that the UV photons create hot electrons on a catalyst metal surface and which interact strongly with adsorbed oxygen to cause the trapped oxygen atoms to dissociate or desorb. The salient point is that adsorbates trap in metastable states before they dissociate, and that hot electrons can stimulate such states efficiently. Experiments showed that gas phase oxygen molecules adsorb first as a superoxo-like specie (molecule singly charged on surface) and are then trapped in a shallow barrier of order 0.1 eV. Then the molecule may overcome the barrier and become a peroxo-like specie (doubly charged) in a barrier of order 0.5 eV. Finally, the molecule may overcome this barrier and dissociate into hot atoms. The existence of precursor phases is apparently fairly common and observed in various forms of platinum, palladium and iridium catalysts. Nolan, P. D.; B. R. Lutz, P. L. Tanaka, J. E. Davis, and C. B. Mullins, xe2x80x9cMolecularly chemisorbed intermediates to oxygen adsorption on Pt (111): A molecular beam and electron energy-loss spectroscopy study,xe2x80x9d Journal Of Chemical Physics Volume 111, Number 8, Aug. 22, 1999. Nolan P D, Lutz B R, Tanaka P L, Mullins C B, xe2x80x9cDirect verification of a high-translational-energy molecular precursor to oxygen dissociation on Pd(111),xe2x80x9d Surface Science v. 419(#1) pp. L1071-L113, Dec. 24, 1998. Nolan, P. D.; B. R. Lutz, P. L. Tanaka, J. E. Davis, and C. B. Mullins, xe2x80x9cTranslational Energy Selection of Molecular Precursors to Oxygen Adsorption on Pt(111),xe2x80x9d Physical Review Letters, VOLUME 81, NUMBER 15 Oct. 12, 1998. Davis, J. E.; P. D. Nolan, S. G. Karseboom, and C. B. Mullins, xe2x80x9cKinetics and dynamics of the dissociative chemisorption of oxygen on Ir(111),xe2x80x9d J. Chem. Phys. 107 (3), Jul. 15, 1997, pp943, 10 pages.
Inverted products can be formed by associative desorption. Experiments have shown that nitrogen molecules formed upon catalytic decomposition of ammonia (cracking) over Ru may show a vibrational population inversion. The associative reaction begins with the atomic separation of the nitrogen atoms being similar to that of the surface catalyst atoms and just slightly greater than that of the ground state of a product nitrogen molecule. Murphy, M. J.; J. F. Skelly, and A. Hodgson; B. Hammer, xe2x80x9cInverted vibrational distributions from N2 recombination at Ru(001): Evidence for a metastable molecular chemisorption well,xe2x80x9d Journal of Chemical Physicsxe2x80x94Apr. 8, 1999xe2x80x94Volume 110, Issue 14, pp. 6954-6962.
That reaction rates can be stimulated and increased by many orders of magnitude with picosecond duration and timing is illustrated by recent experiments depicted in a technical publication. Bonn, M.; S. Funk, Ch. Hess, D. N. Denzler, C. Stampfl, M. Scheffler, M. Wolf, G. Ertl, xe2x80x9cPhonon- Versus Electron-Mediated Desorption and Oxidation of CO on Ru(0001),xe2x80x9d Science, Volume 285, Number 5430 Issue of Aug. 13, 1999, pp. 1042-1045.
The stretched molecule represents the initial condition where the atomic separation during the vibrational oscillation starts with the association reaction at the extrema, defining a reaction product in the highest excited state. It is noted xe2x80x9cVibrationalxe2x80x9d modes also include the vibration of any specie on the surface against that surface.
Simple reactant radicals on the catalyst surface may preferentially form in mechanically simple ways, which often strongly favor a single vibrational mode for the energy to concentrate, again favoring an inverted population.
Furthermore, mono-atomic oxygen atoms supplied externally to the catalytic surface may cause a population inversion in the products of carbon monoxide reaction to carbon dioxide and in the surface catalyzed oxidation of hydrogen.
Heretofore, the oxygen adsorption process wasted approximately half the reaction energy as heat on the catalyst surface. Therefore, a new method to conserve such energy and extract it into useful energy is highly desired.
The present invention is directed to a method and system for using a catalyst and reactants to create the xe2x80x9csimple, energetic atomsxe2x80x9d needed for the generation of the inverted population. In one embodiment, the present invention captures the reaction energy based on the principle that some energetic atoms reacting on a catalytic surface produce products exhibiting a population inversion.
This invention creates population inverted reaction products from fuel and oxidizer reactions on a catalyst surface. A laser operating on the inverted population would efficiently extract the energy from the system. One embodiment uses the hot atom produced during dissociative adsorption of oxygen on catalyst surfaces to provide energetic oxygen free radicals on those surfaces and to cause direct and prompt reaction with a fuel specie, also on the catalyst surface, which biases reactions towards formation of population inverted products. Examples of fuel specie include, but are not limited to, hydrogen, a hydroxyl, a carbon monoxide or a hydrocarbon fragment.
Another embodiment of this invention creates a population inversion by biasing the reaction by choice of catalyst species to form product molecules that are stretched at the moment of desorption from the catalyst surface. Another embodiment creates the population inversion by biasing the reactants by choice of catalyst to cause simple reactants with a large fraction of their energy available upon associative desorption. Another embodiment uses a solid-state method to provide hot electrons directly, and without the use of UV light, which in turn stimulates dissociation of the precursor, peroxo-chemisorbed oxidizer, and cause an avalanche of surface reactions.
In one embodiment, the present invention uses a laser to extract the energy from an inverted population, resulting in conversion of a substantial fraction, and in some cases a majority, of the chemical reaction energy into one or several, nearly monochromatic, coherent beams of light. Such a beam retains the high quality of the energy and is most useful because it can be efficiently converted into electricity, for example, by passing a monochromatic beam into a photovoltaic cell with band gap slightly smaller than the beam photon energy, and equally efficiently into mechanical forces through other means.